Double shutter weir



Jan. 29, 1935. 9 A; v. Lu'rZ 1,989,457

DOUBLE SHUTTER WEIR Filed Feb. 1, 1953 Fly. l.-

I a d //VVENTOR H 10 46; xi;

A TTORNEY Patented Jan. 29, 1935 UNITED: s TATES 1,989,457 I, bo UBLE sHUTrER-WELR Alois Victor Lutz, Zurich; Switzerland Application February 1,

1933, Serial No. 654,586

In Germany February 8, 1932 3 Claims.

The invention relates to a double shutter weir actuated by the pressure of the dammed water, two examples being illustrated in cross section in Figures 1 and 2 respectively of the accompanying drawing.

In the known weirs of this kind the upper shutter is provided with an extension directed downstream and supported on the back of the lower shutter, or else the upper shutter is supported with its under side resting directly on the under shutter. In both cases it has been found in practice that water is lost through the slit formed at the top along the line of contact of the shutters, particularly with the shutters in lowered position when this slit is under increased pressure from the internal water and is also under a suction effect produced by the Water flowing over the weir.

Such loss of water must be made good by a continuous flow of upstream water, which leads to undesirable deposition of sand suspended in the water, in the weir chamber. If the flow of water is insufiicient the weir may descend unnoticed.

These faults are overcome according to the invention by the line of contact of the shutters being transferred from the down stream to the upstream side, the under shutter extending up to the water level when the weir is raised and being provided with a downward extension directed upstream, upon which the upper edge of the upper shutter rests. The escape of water through the slit between the two shutters is thus prevented. Furthermore owing to the extension on the lower shuttenthe upper shutter can be made shorter and therefore lighter. It is true this involves greater length of and therefore greater bending stress in the lower shutter, but 40 suflicient space is available to provide it with high supports. In the case of the upper shutter however it is desirable to make the supports as low as possible because otherwise the end of the lower shutter scrapes their lower sides or the axial separation of the shutters must be increased.

Figure l is a longitudinal section of one embodiment of the invention,

Figure 2 is a longitudinal section of another 50 embodiment of the invention, and

Figure 3 is a detail plan applicable to both Figures 1 and 2.

Referring now to the examples shown in the drawing, the two shutters 1 and 2 which pivot upon horizontal axes 3 and 4 respectively, form,

just as in the known double shutter weirs, a closed chamber 5 which can be put into communication with the upstream water or the downstream water at will, to raise or lower (dotted line position) the weir respectively. 0 Communication is established in the manner usual in weirs of this class by ports and passages in one' (or both) of the side walls of the weir channel, the ports being provided with controllable sliding shutters.

Thusa chamber 13 is formed in one side wall of the weir having a port communicating with the weir chamber 5. By means of a controllable sliding shutter 12 the port 10 can communicate through a passage 14 with a port 15 open to the downstream water, while another sliding shutter 11 controls communication between the chamber 13 and the upstream water.

The lower shutter 2 reaches to the up-stream waterlevel 6. It has a downwardly directed extension upon which the upper edge of the upper shutter rests by means of a roller 8.

The junction between the shutter'2 and extension 7 is rounded oiT cylindrically. This rounding 01f ensures that the roller always remains against the surface of the shutter. 2 or the extension 7 and no reentrant space leading to eddying and consequent deposition is formed at any position of the shutters 1, 2. This rounding ofi further ensures gradual change of the direction of pressure exerted through the roller 8 and it facilitates the flow of water over the crown of the weir. Preferably the extension '7 is substantially perpendicular to the shutter 2.

The upper shutter 1 is shown straight in Figures 1 and 2 but it may be slightly cambered upwards.

In the embodiment of Figure 2 the uppermost part of the lower shutter is in the form of a closed tube 9 which forms the rounded junction with the extension. Its upthrust enables the weight of the shutter to be almost completely balanced so that quite a small fall between the up-stream and down-stream water levels suffices to raise the weir. This tube also serves effective ly to stiffen the lower shutter.

What I claim is:

1. In a. double shutter weir, the combination of a lower shutter pivoted on atransverse axis at the bottom of the downstream channel and I I extending upstream, a downward extension rigid on the outer end of said shutter, an upper shutter pivoted on a transverse axis at the bottom of the upstream channel and having its free end slidably resting on said extension, and means for 2 1 putting the Space between said shutters into communication with the upstream or downstream water at will.

2. In a double shutter weir, the combination of a lower shutter pivoted on a transverse axis at the bottom of the down-stream channel and extending upstream, a downward extension, a rounded portion forming a rigid junction between the outer end of said lower shutter and said ex-' tension,, an upper shutter pivoted on a transverse axis at the bottom of the upstream channel and having its free end slidably resting on said extension, and means for putting the space between said shutters into communication with the upstream or downstream water at will.

3. In a double shutter weir, the combination of a lower shutter pivoted on a transverse axis at the bottom of the downstream channel and extending upstream, a downward extension, a float in the form of a closed tube forming a round topped rigid junction between the outer end of said lower shutter and said extension, an upper shutter pivoted on a transverse axis at the bottom of the upstream channel and having its free end slidably resting on said extension, and means for putting the space between said shutters into communication with the upstream or downstream water at will.

ALOIS VICTOR LUTZ. 

